Low Voltage, Resistor-Programmable, Thermostatic Switch Data Sheet AD22105 FEATURES FUNCTIONAL BLOCK DIAGRAM User-programmable temperature setpoint AD22105 2.0C maximum ambient setpoint accuracy 200k 4.1C typical hysteresis R 8 PULLUP 1 NC Wide supply range: 2.7 V to 7.0 V Wide temperature range: 40C to +150C V OUT 2 7 S Low power dissipation SET- POINT APPLICATIONS GND R 6 SET 3 Industrial process control TEMPERATURE NC Thermal control systems 4 5 NC SENSOR CPU monitoring Computer thermal management circuits Figure 1. Fan control Handheld/portable electronic equipment GENERAL DESCRIPTION The AD22105 is a solid state thermostatic switch. Requiring only one external programming resistor, the AD22105 can be set to switch accurately at any temperature in the 40C to +150C wide operating range. Using a novel circuit architecture, the AD22105 asserts an open-collector output when the ambient temperature exceeds the user-programmed setpoint temperature. The AD22105 has approximately 4C of hysteresis, which prevents rapid thermal on and off cycling. The AD22105 operates on a single power supply voltage from 2.7 V to 7.0 V, facilitating operation in battery-powered applications as well as in industrial control systems. Because of low power dissipation (230 W at 3.3 V), self heating errors are minimized, and battery life is maximized. An optional internal 200 k pull-up resistor is included to facilitate driving light loads such as complementary metaloxide semiconductor (CMOS) inputs. Alternatively, a low power light emitting diode (LED) indicator can be driven directly. Rev. A Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 19962018 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com 02099-001AD22105 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Effect of Resistor Tolerance and Thermal Drift on Setpoint Accuracy .........................................................................................8 Applications ....................................................................................... 1 Hysteresis and Self Heating ..........................................................9 General Description ......................................................................... 1 Output Section ...............................................................................9 Functional Block Diagram .............................................................. 1 Mounting Considerations ............................................................9 Revision History ............................................................................... 2 Thermal Environment Effects .....................................................9 Specifications ..................................................................................... 3 Using the AD22105 as a Cooling Setpoint Detector ................9 Absolute Maximum Ratings ............................................................ 4 Applications Information .............................................................. 10 Thermal Resistance ...................................................................... 4 Electromagnetic Interference (EMI) Suppression ................. 10 ESD Caution .................................................................................. 4 Leakage at the RSET Pin ............................................................... 10 Pin Configuration and Function Descriptions ............................. 5 Outline Dimensions ....................................................................... 11 Typical Performance Characteristics ............................................. 6 Ordering Guide .......................................................................... 11 Theory of Operation ........................................................................ 8 The Setpoint Resistor ................................................................... 8 REVISION HISTORY 10/2018Rev. 0 to Rev. A Update Format .................................................................... Universal Changes to Features Section............................................................ 1 Changed Product Description Section to Theory of Operation Section ................................................................................................ 8 Changed Application Hint Section to Applications Information Section .............................................................................................. 10 Updated Outline Dimensions ....................................................... 11 Changes to Ordering Guide .......................................................... 11 1/1996Revision 0: Initial Version Rev. A Page 2 of 11